The invention relates to a sewing machine, and more particularly it relates to a housing structure of the sewing machine. Generally a machine housing is divided into two parts for assembling the components of the sewing machine. It has therefore been a problem how to effectively and rapidly connect the two parts of the machine housing with a required precision during a mass-production of sewing machines.
In the conventional sewing machines, the machine housing is, as shown in FIG. 1, composed of a machine arm 1 including a vertical hollow standard 1a and a machine bed 2 with an upper flat face 3. Therefore the machine arm 1 has a juncture edge 4 provided at the lower end of the standard, and the machine bed 2 has a juncture part 4a provided at the upper edge thereof. The connecting operation of the two structures 1, 2 is required at the lower level of the machine housing. The two structures 1, 2 are adjustedly connected to each other by a number of threaded bolts 5, and a number of pins 6 are employed for positional adustment of the structures 1, 2. The connecting operation is to be implemented at the bottom of the machine bed 2 when the machine housing is put in the horizontal position. With such a bulky and heavy machine housing, it is very burdensome to implement the connecting operation in such a manner. Moreover it is very difficult to positionally adjust the arm 1 with respect to the machine bed 2 or vice versa so that the needle supported in the bracket 10 of the arm 1 may be precisely aligned with the needle drop hole 9 of the needle plate 8 carried on the upper flat face 3 of the machine bed 2. It may be said that all such difficulties in the connecting operation result from the fact that the juncture parts 4, 4a are far from the bracket 10 of the machine arm 1.
On the other hand, according to the conventional machine in which housing structure 11 as shown in FIG. 2 which is not divided into two parts, but made up as an integral one, it becomes necessary to mount the components of the sewing machine with a severe precision. for example, the needle bar with the needle has to be mounted to the bracket of the machine arm with a precision, so that the needle may be precisely aligned with the needle drop hole of the needle plate. Such a precision is required with respect to so many locations of mechanisms of the sewing machine.